Collecting cylinders of variable diameter in different designs are generally known. Such collecting cylinders are required to regulate the paper pull if the products collected have different thicknesses.
Collecting cylinders with circumferential elements extending from point holes to point holes have also become known through the Swiss Patent 417,646. Neither in the one nor in the other design are the circumferential elements adjusted by way of eccentric shafts.
Practical arrangements have been provided including a collecting cylinder for point folders of rotary machines in which the cylinder circumferential surface includes a number of circumferential segments which are positioned adjacent one another. The segments are disposed extending groupwise from point holes to point holes supported at their two ends on bearings and are movable outwardly. The circumferential elements of such an arrangement are supported at their two ends on bearings on ecentric shafts, by means of which a radial adjustment of the circumferential elements becomes possible. So that this adjustment always takes place simultaneously for each group of circumferential elements, each ecentric shaft carries a pinion gear, which engages a spur-toothed wheel that is rotatably supported on bearings centrically to the collecting cylinder (see also German Patent 2,040,494). By changing the angle between this spur-toothed wheel and the collecting cylinder, the radial position of the circumferential segments and thereby the active diameter of the collecting cylinder are also automatically changed.
The above-mentioned constructions have the disadvantage that the circumferential segments make difficult or even prevent any access to the inner parts of the collecting cylinder, so that, for tasks such as exchanging or replacing folding plates, they must first of all be removed from the collecting cylinder, to which accessibility in the folding apparatus is limited in any case.
The above-mentioned gearwheel connection has a further disadvantage. If the setting of the diameter of the collecting cylinder remains the same for a long time, this connection can become contaminated by paper dust, etc. to such an extent, that it seizes or jams during a subsequent adjustment.